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Aqualntel Pty Ltd t: +7 5414 7185 m: 0400 436 391 e: [email protected] ACN: 153 875 953 ABN: 83 572 946 845 Document Information oes, Integrated Water Management Plan Report Title Coles Tavern Development Version Rev C Author(s) Brendon Bolt Approved by KMcK (RPEQ 09298) Signed Ywe Kirnay e Date 8 May 2013 . Doc No 201018-RPT-001 Distribution TOD Consulting Engineers
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Executive Summary AquaIntel Pty Ltd was commissioned by TOD Consulting Engineers to prepare an Integrated Water Management Plan (IWMP) for the proposed development of a tavern, bottle shop, residential, commercial and specialty shop site as part of Noosa Fair at Noosa Junction. The site is currently fully developed and operates as the Noosa Bowls Club. The site itself consists of the club house and three bowling greens with the rest of the site being carpark and access. The majority of the site grades from the east (Lanyana Way) to the west (Noosa Drive). A small part of the site drains back to towards Lanyana Way. Currently stormwater from the site is collected via internal drainage and discharged into Pinaroo Rotary Park to the west. The site does not have any external catchments that contribute to the site. Environmental best management practices are proposed for treatment of stormwater flowing through the site. Stormwater will be treated by a number of treatment devices prior to discharge to the receiving environment. The stormwater treatment train for the site will include collection of runoff from roofed areas in rainwater tanks for re-use, with overflow and runoff from carparks directed into bioretention areas prior to discharging off-site. Non-worsening of peak flows has been demonstrated through the incorporation of detention systems in two of the sub-catchments. The catchments draining to the west do not require mitigation measures as the catchment area has been reduced from the existing to the developed scenarios. This Integrated Water Management Plan demonstrates that effective treatment of stormwater at the proposed development can be achieved through the application and appropriate design of Water Sensitive Urban Design (WSUD) principles in accordance with legislative requirements and best practice guidelines. The treatment train proposed for the development site achieves the performance criteria set by the Sunshine Coast Regional Council. Through the implementation of detention systems within the catchments non- worsening criteria has been achieved to ensure no downstream impacts.
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Contents EXECUTIVE SUMMARY I 1 INTRODUCTION 1 1.1 SITE CHARACTERISTICS 1 2 STORMWATER QUALITY 4 2.1 DESIGN OBJECTIVES 4 2.1.1 TYPICAL POLLUTANTS 4 2.1.2 OPERATIONAL DESIGN WATER QUALITY OBJECTIVES 4 2.2 STORMWATER QUALITY TREATMENT 5 2.2.1 STRATEGY 5 2.3 MODELLING APPROACH 6 2.3.1 MUSIC PARAMETERS 6 2.3.2 CATCHMENT AREAS 7 2.3.3 MUSIC MODEL LAYOUT 7 2.4 TREATMENT MEASURES 9 2.4.1 RAINWATER TANKS 9 2.4.2 BIORETENTION SYSTEM 10 2.5 RESULTS 13 3 STORMWATER QUANTITY 14 3.1 EXISTING SCENARIO 14 3.2 RATIONAL METHOD CALIBRATION 15 3.3 DEVELOPED SCENARIO 18 3.4 MITIGATED SCENARIO 20 4 CONCLUSIONS 21 5 REFERENCES 22 FIGURES Figure 1: Locality Plan 2 Figure 2: Proposed Development Layout 3 Figure 3: Conceptual Treatment Train 5 Figure 4: Model Layout 7 Figure 5:Stormwater Quality Catchment Plan 8 Figure 6: Stormwater Quality Management Strategy 12 Figure 7: Existing Scenario WBNM Sub-Catchments 17 Figure 8: Developed Scenario WBNM Sub-Catchments 19
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TABLES Table 1: Pollutants typically generated during the operational phase 4 Table 2: Site stormwater quality objectives (operational phase) 4 Table 3: MUSIC Base and Storm Flow Concentration Parameters - Commercial 6 Table 4: MUSIC Runoff Generation Parameters - Commercial 6 Table 5: Impervious Percentage 7 Table 6: Catchment Areas 7 Table 7: MUSIC Rainwater Tank Demands 10 Table 8: MUSIC Rainwater Tank Parameters 10 Table 9: Bioretention Basin Design Parameters 11 Table 10: MUSIC Results – Load-Based Pollutant Outputs at Outlet to Site 13 Table 11: MUSIC Results – Load-Based Pollutant Outputs for Road Area 13 Table 12: WBNM Sub-Catchment Fraction Impervious Values – Existing Scenario 14 Table 13: Existing Scenario WBNM Outlet Peak Flows 15 Table 14: Rational Method Calibration Summary (Total Catchment) 15 Table 15: Rational Method Peak Flows Versus WBNM Peak Flows 16 Table 16: WBNM Sub-Catchment Fraction Impervious Values – Developed Scenario 18 Table 17: Developed Scenario WBNM Outlet Peak Flows 18 Table 18: Storage and Outlet Details of Detention System 20 Table 19: Comparison of Existing, Developed and Mitigated WBNM Outlet Peak Flows 20 APPENDICIES Appendix 1: Rational Method and WBNM Results 23
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1 Introduction
AquaIntel has been commissioned by TOD Consulting Engineers on behalf of Coles to
prepare an Integrated Water Management Plan (IWMP) to support their Material
Change of Use Applications for the development of the existing Noosa Bowls Club
into a residential, commercial, specialty shops, bottle shop and tavern at Lanyana
Way, Noosa Junction (Lot 3 SP884396).
The Pollution Load Reduction Targets and non-worsening criteria as outlined in the
Planning Scheme Policy No 6 – Operational works (section 7) have been adopted in
this investigation. This SCRC planning scheme policy is outlined as an acceptable
solution as part of the Integrated Water Management Code. The purpose of this
IWMP is to identify the preliminary stormwater quality, detention and water re-use
options that could be implemented within the site to achieve elements of the code.
The objectives of this IWMP are to:
• Ensure the proposed development maintains or improves the environmental
values of the receiving waters within the receiving catchment throughout the
operational phase;
• Consider suitable Stormwater Quality Improvement Devices (SQID’s) based
on Water Sensitive Urban Design (WSUD) principles;
• Recommend an appropriate stormwater treatment strategy for the proposed
development that complies with Sunshine Coast Regional Council (SCRC)
water quality objectives;
• Ensure the development achieves non-worsening of stormwater flows
downstream of the site.
1.1 Site Characteristics
The proposed development will be located within the Noosa Fair shopping precinct
at Noosa Junction. The location of the site is shown in Figure 1. The site where the
development is proposed currently operates as the Noosa Bowls Club. The site
grades from the southeast corner at elevation of approximately 21 m AHD to the
southwest boundary at an elevation of approximately 18m AHD.
There are no external catchments which influence the site. A natural gully runs
south to north to the west of the site. Majority of the site drains to this gully. A
portion of the site currently drains to the existing drainage network in the north east
corner. This flow path will be maintained.
The proposed development layout is provided in Figure 2.
1
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LEGEND Data Source Notes:
Project: Integrated Water Management Plan –
Noosa Fair
Site Locality
Figure 1 Locality Plan
Date: 28/01/13
Drawn by: BB
Page 8
LEGEND Data Source Notes: Project: Integrated Water Management Plan – Noosa Fair
Proposed development layout provided by TOD
Consulting for use in this investigation.
Figure 2 Development Layout
Date: 07/05/13
Drawn by: BB
Page 9
2 Stormwater Quality
2.1 Design Objectives
This report identifies the stormwater quality management objectives for the
operational phase (post-construction phase) of the proposed development.
Construction based stormwater quality management objectives will need to be
addressed as part of operational works documentation.
2.1.1 Typical Pollutants
Typical pollutants generated during the operational phases of a development are
outlined in Table 1. These pollutants are to be addressed in the management of
water quality discharged from a development site. Construction based pollutants
will be managed through appropriate erosion and sediment control measures.
Table 1: Pollutants typically generated during the operational phase
Pollutant Potential Source
Construction packaging, construction waste materials,
Litter
paper, food packaging
Sediment Exposed soils and stockpiles
Hydrocarbons Fuel or oil spillage, equipment leakage
Toxic materials Washwaters, cement slurry, paints, cleaning agents
Acid or Alkaline substances Acid sulphate soils, cement slurry, washwaters
Oxygen demanding substances Organic or chemical matter
Nutrients Nitrogen, phosphorous
Pathogens/Faecal coliforms Sewage
Heavy metals Sediment runoff
Surfactants Detergents, cleaning agents
2.1.2 Operational Design Water Quality Objectives
Water quality objectives or performance criteria for the proposed development are
those stipulated in the SRC Planning Scheme Policy No 6 – Operational works
(Section 7). The applicable water quality design objectives for the site are shown in
Table 2 below.
Table 2: Site stormwater quality objectives (operational phase)
Minimum reductions in mean annual loads from unmitigated development (%)
Total Suspended Total Phosphorous Total Nitrogen Gross pollutants
Solids (TSS) (TP) (TN) >5 mm
80 60 45 90
4
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2.2 Stormwater Quality Treatment
2.2.1 Strategy
Environmental best management practices are proposed for treatment of
stormwater flowing through the site. Two (2) separate scenarios were analysed
which represent:
1. Post Development: with No Mitigation Scenario (Unmitigated); and
2. Post Development: with Mitigation Scenario (Mitigated).
The treatment train for the proposed development is shown in Figure 3. Runoff
from roofed areas will be collected in rainwater tanks and re-used for irrigation and
non-potable internal uses. The tanks have been sized to achieve a minimum 80%
reliability. Overflow from the tanks and road runoff will be treated via bioretention
systems prior to discharge from the site.
ROAD ROOFED AREA
RAINWATER TANK
BIORETENTION SYSTEM
RECEIVING ENVIRONMENT
Figure 3: Conceptual Treatment Train
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2.3 Modelling Approach
2.3.1 MUSIC Parameters
An assessment of stormwater runoff quality from the proposed development site
has been assessed using the Cooperative Research Centre for Catchment
Hydrology’s (CRCCH) Model for Urban Stormwater Improvement Conceptualisation
(MUSIC). MUSIC is a decision support tool, used to plan and design appropriate
urban stormwater management systems at the conceptual level. MUSIC Version
5.1.16, released in 2012, was used in this assessment.
Climate data for the catchment was sourced from the MUSIC model database. The
rainfall and evaporation data template for this site has been based on data from
Nambour from 1/1/1989- 31/12/1998 with six (6) minute rainfall duration.
The “MUSIC Modeling Guidelines” (Water By Design, 2010) was used as the basis for
constructing the MUSIC model. The default parameters of the MUSIC model were
used in representing the treatment nodes (where applicable). Table 3 and Table 4
outline the adopted source node parameters that were used in the MUSIC model.
Table 3: MUSIC Base and Storm Flow Concentration Parameters - Commercial
Total Suspended Total
Total Nitrogen
Solids Phosphorous
(Log10 mg/L)
Land Use Parameter (Log10 mg/L) (Log10 mg/L)
Storm Base Storm Base Storm Base
Flow Flow Flow Flow Flow Flow
Mean 1.30 0.001 -0.89 0.001 0.37 0.001
Roof
Std Deviation 0.38 0.001 0.34 0.001 0.34 0.001
Mean 2.43 0.78 -0.30 -0.60 0.37 0.32
Road
Std Deviation 0.38 0.39 0.34 0.50 0.34 0.30
Table 4: MUSIC Runoff Generation Parameters - Commercial
Parameter Commercial
Rainfall Threshold (mm) 1
Soil Capacity (mm) 18
Initial Storage (%) 10
Field Capacity 80
Infiltration Capacity Coefficient a 243
Infiltration Capacity Coefficient b 0.6
Initial Depth (mm) 50
Daily Recharge (%) 0
Daily Drainage (%) 31
Daily Deep Seepage Rate (%) 0
6
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The fraction impervious value applied for each of the source nodes are detailed
below in Table 5.
Table 5: Impervious Percentage
Impervious Percentage Roof Road
% 100% 90%
2.3.2 Catchment Areas
The development site has been split into four (4) sub-catchments. Two catchments
represent the tavern site which drains to two outlets. The other two catchments
represent the new road area which also drains to two different outlets (drainage
reserve and Lanyana Way). Catchment A and C have buildings whose roofed areas
are modeled roof. The rest of each catchment is modeled as road. Table 6 outlines
the catchment areas represented within the MUSIC model. The stormwater quality
catchments are provided in Figure 5.
Table 6: Catchment Areas
Catchment Area Roof Road Total
A 1.11 0.36 0.75 1.11
B 0.65 0.03 0.62 0.65
C 0.46 0.30 0.16 0.46
D 0.31 0.04 0.27 0.31
TOTAL 2.52 0.74 1.792 2.52
2.3.3 MUSIC Model Layout
As the management of urban stormwater needs to take a holistic approach, a
number of management measures need to be implemented in series to form a
treatment train. The correct utilisation of various devices within the treatment train
is imperative to target the desired pollutants, from the gross solids to the fine
colloidal partials. Figure 4 shows the MUSIC model layout for the development.
Figure 4: Model Layout
7
Page 13
LEGEND Data Source Notes: Project: Integrated Water Management Plan – Noosa Fair
Proposed development layout provided by TOD
Consulting for use in this investigation.
Water Quality Catchment Boundary
Figure 5 Water Quality Catchment Plan
Date: 07/05/13
Drawn by: BB
Page 14
2.4 Treatment Measures
The various treatment measures proposed to be implemented within this
development are outlined below. They are made up of rainwater tanks and
bioretention system for stormwater reuse. The localities of the measures are
detailed in Figure 6.
2.4.1 Rainwater Tanks
Through appropriate design of rainwater tanks it has been found that significant
reductions in run-off can be achieved. Rainwater tanks not only provide temporary
detention of stormwater run-off, but also provide a significant alternative for water
supply uses. Collected roof water is suitable for garden irrigation or toilet flushing
with no additional treatment.
An additional benefit to rainwater tanks is that the detention of stormwater flows
can alter the pollutant transportation characteristics of a catchment. Rainwater
tanks can be incorporated into building design so that they do not impact on the
aesthetics of an urban development. Legislation introduced by the Queensland
State Government regarding water saving targets have mandated the inclusion of
rainwater tanks in all new developments state-wide unless an exemption has been
granted.
Rainwater tanks have been modeled as a lumped tank to represent the entire
development. Sizing of each tank volume has been modeled in MUSIC using
estimated demands for each use to achieve a minimum 80% reliability. The
demands of each use on the site are highlighted in below in Table 7. Irrigation of the
site landscape will be sourced from the Tavern tank. Landscaping area has been
estimated as 10% of the carpark area, irrigating at a rate of 548mm/yr. The annual
irrigation demand scaled by daily PET was calculated as 311KL/yr.
9
Page 15
Table 7: MUSIC Rainwater Tank Demands
Units Average Demand Daily
Use Usage Persons (L/P/D) Demand
A-Residential Toilet 27 1.2 26 842
Laundry 27 1.2 35 1,134
A-Commercial Toilet 10 2 25 500
B-Shops Toilet 3 2 25 150
C-Tavern Toilet 1 - - 1,800
D-Shops Toilet 4 2 25 200
Based on the roof catchment areas and the demands estimated for each use, the
rainwater tank modeling parameters are detailed in Table 8.
Table 8: MUSIC Rainwater Tank Parameters
Parameter A-Res A-Comm B-Shops C-Tavern D-Shops
Total Tank Volume (KL) 30 5 3 60 4
2
Surface Area (m ) 10 2 1 25 1
Overflow Pipe (mm) 90 90 90 90 90
Annual Demand Scaled
- - - 311 -
by Daily PET (kL/yr)
Daily Demand (kL/d) 1.98 0.45 0.15 1.80 0.20
2.4.2 Bioretention System
Bioretention systems use ponding above a treatment surface to maximise the
volume of runoff flowing through the filtration media. They typically convey flows
above the design event through overflow pits. The treatment system operates by
firstly filtering surface flows through surface vegetation and then percolating runoff
through prescribed filtration media. This media provides treatment through fine
filtration, extended detention and biological uptake of nutrients. They also provide
flow retardation for smaller events and are particularly efficient in removing
nutrients. These devices can be installed at various scales, from planter boxes in
streetscape to within large detention basins.
10
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The bioretention systems proposed to treat the runoff generated from the
development site are to be located within the landscape area within the carpark
area. Runoff from the carpark areas are to be directed to these small bioretention
basins, before entering the underground drainage network.
Roadside bioretention cells are proposed to treat runoff from the new road.
As these systems take approximately 12-24hrs to drain, the maximum depth of
pondage allowed to occur over the filter area has been limited to 200mm in the
carpark and 100mm in the road reserve. The depth of the filter media has been
limited to 500mm. The basin is to be planted out with native species which are
adaptable to a wet/dry soil environment. The basin will require maintenance such as
weeding and replanting if plants are damaged or die. Table 9 summarises the
proposed design parameters for the bioretention basin for this development.
As bioretention systems are scalable, modeling has been undertaken representing
each sub-catchment as a whole. Final sizing and location of bioretention systems
will be dependent on the detailed design of the drainage catchments / system. The
areas identified in Table 9 are the minimum areas that are to be implemented within
each sub-catchment. Indicative bioretention locations are highlighted in Figure 6.
Table 9: Bioretention Basin Design Parameters
Parameter A B C D
Extended Detention Depth (m) 0.2 0.2 0.2 0.1
2
Storage Surface Area (m ) 120 65 45 40
2
Filter Media Area (m ) 90 50 35 30
Unlined Filter Media Perimeter (m) 0.01 0.01 0.01 0.01
Saturated Hydraulic Conductivity (mm/hr) 200 200 200 200
Filter Depth (m) 0.5 0.5 0.5 0.5
TN Content of Filter Media (mg/kg) 800 800 800 800
Orthophosphate Content of Filter Media
55 55 55 55
(mg/kg)
Exfiltration Rate (mm/hr) 0.0 0.0 0.0 0.0
Overflow Weir (m) 2.0 2.0 2.0 2.0
11
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NOTES:
1: Locations and sizing of treatment devices are indicative, with final placement subject to
detailed design.
LEGEND Data Source Notes: Project: Integrated Water Management Plan – Noosa Fair
Proposed development layout provided by TOD
Water Quality Catchment Boundary Consulting for use in this investigation.
Roadside Bioretention Cell
Figure 6 WSUD Locality Plan
Carpark Bioretention System
Date: 07/05/13
Rainwater Tank
Drawn by: BB
Page 18
2.5 Results
MUSIC modelling of the proposed treatment train for the tavern site at Noosa Fair,
was performed to ensure the identified load based Water Quality Objectives were
achieved. Table 10 and Table 11 present the overall load-based outputs at the
receiving node. It is to be noted that the site and road catchments have been
reported separately to demonstrate compliance with the WQO.
Table 10: MUSIC Results – Load-Based Pollutant Outputs at Outlet to Site
Reduction
Unmitigated Mitigated Target
Pollutant Achieved Compliance
(kg/yr) (kg/yr) Reduction
(%)
Flow 21.10 19.20 8.9 - -
TSS 5,500 1,030 81.3 80%
TP 10.4 3.9 62.5 60%
TN 67.4 32.2 52.2 45%
GP 480 0 100 90%
Table 11: MUSIC Results – Load-Based Pollutant Outputs for Road Area
Reduction
Unmitigated Mitigated Target
Pollutant Achieved Compliance
(kg/yr) (kg/yr) Reduction
(%)
Flow 12.9 12.5 2.8 - -
TSS 4,680 914 80.5 80%
TP 8.19 2.9 64.5 60%
TN 41.1 21.8 47 45%
GP 293 0 100 90%
13
[OCR of page images]
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aquaintel
2.5 Results
MUSIC modelling of the proposed treatment train for the tavern site at Noosa Fair,
was performed to ensure the identified load based Water Quality Objectives were
achieved. Table 10 and Table 11 present the overall load-based outputs at the
receiving node. It is to be noted that the site and road catchments have been
reported separately to demonstrate compliance with the WQO.
Table 10: MUSIC Results — Load-Based Pollutant Outputs at Outlet to Site
Reduction
Unmitigated Mitigated : Target .
Pollutant (kg/yr) (kg/yr) nee) Reduction Compliance
Flow 21.10 19.20 8.9 - -
Tss 5,500 1,030 81.3 80% v
TP 10.4 3.9 62.5 60% v
TN 67.4 32.2 52.2 45% v
GP 480 ) 100 90% v
Table 11: MUSIC Results — Load-Based Pollutant Outputs for Road Area
Reduction
Unmitigated Mitigated . Target .
Ach
Pollutant (kg/yr) (kg/yr) cI ee Reduction Compliance
Flow 12.9 12.5 2.8 - -
TSS 4,680 914 80.5 80% v
TP 8.19 2.9 64.5 60% v
TN 41.1 21.8 47 45% v
GP 293 0 100 90% v
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3 Stormwater Quantity
The objective of this component of the study is to investigate the potential impact
that the proposed development will have on peak flows discharging downstream of
the site. Where any increases of peak flows are found, potential mitigation options
will be investigated in the form of a detention system.
Hydrologic modelling of the catchment has been carried out using WBNM software
developed jointly by the University of Wollongong, Rienco Consulting and Balance
R&D. The January 2007 version has been used for this investigation. A peak flow
rational method calibration has also been carried out.
Modelling has been carried out for the 2, 10 and 100 year ARI storm events. The
following scenarios have been investigated:
1. Existing Scenario
2. Developed Scenario
3. Mitigated Scenario
3.1 Existing Scenario
Sub-catchments delineated for the WBNM model have been based on detailed
survey and existing drainage details provided for the site. The existing scenario
WBNM sub-catchment layout is shown in Figure 7 of this report. The WBNM model
has been split into 4 sub-catchments with a total combined catchment area of 2.32
ha.
Sub-catchment fraction impervious values have been calculated based on aerial
imagery data. The existing scenario sub-catchment areas and fraction impervious
values for each sub-catchment are tabulated below in Table 12.
Table 12: WBNM Sub-Catchment Fraction Impervious Values – Existing Scenario
Existing Scenario
WBNM Sub-Catchment Area (ha)
Impervious (%)
SUBA 1.24 58
SUBB 0.77 89
SUBC 0.34 90
SUBD 0.17 90
TOTAL 2.52 -
The WBNM model has been calibrated to Rational Method derived peak flows at the
outlet of Catchments A and B which flow to drainage reserve to the west of the site
(WBNM catchment node ‘Outlet1’). Details of the Rational Method calibration are
provided in Section 3.2.
14
Page 20
The WBNM model has been calibrated by adjusting rainfall loss rates and by
adjusting the WBNM catchment lag parameter. The value of the catchment lag
parameter adopted for the investigation is 1.8, which is within the accepted range of
values provided in the WBNM technical reference manual. As the existing site and
developed site are largely impervious (carpark, road and roof) and hard pervious
(bowling green) the rainfall loss rates adopted for this investigation are an initial and
continuing loss of 5mm and 0mm for pervious, and 1mm and 0mm for impervious.
WBNM modelling has been carried out for the range of standard design ARI events
ranging from 2 years up to 100 years. Modelling has also been carried out for the
full range of standard design event storm durations ranging from 15 minutes up to 3
hours. Peak flows tabulated in this report represent the peak values extracted from
this range of storm events.
Table 13: Existing Scenario WBNM Outlet Peak Flows
2 year ARI 10 year ARI 100 year ARI
Catchment
(m3/s) (m3/s) (m3/s)
Outlet 1 0.73 1.02 1.40
Outlet 2 0.14 0.19 0.26
Outlet 3 0.07 0.10 0.14
3.2 Rational Method Calibration
The existing scenario WBNM model has been calibrated to Rational Method derived
peak flows at the outlet of the catchment draining to the drainage reserve to the
west of the site (WBNM catchment node ‘Outlet 1’). Calibration has been achieved
by adjusting rainfall losses and the catchment lag parameter. The adopted
calibration parameters are detailed in the Section 3.1.
A summary of the Rational Method calculation is provided below in Table 14 and
additional details of the Rational Method calculation are provided in Appendix 1 of
this report.
Table 14: Rational Method Calibration Summary (Total Catchment)
Parameter Value
Time of Concentration (tc) 6 minutes
Catchment Area 2.01 hectares
C10 Value 0.87
100 year Rainfall Intensity (6 minute duration) 302 mm/hr
A comparison of peak Rational Method flow rates compared with peak WBNM
model flow rates are provide in Table 15 below.
15
Page 21
Table 15: Rational Method Peak Flows Versus WBNM Peak Flows
ARI Rational Method WBNM Difference
(Years) m3/s m3/s (%)
2 0.64 0.73 12.3
10 1.02 1.02 0.0
100 1.76 1.40 -25.6
The above results show that a reasonable peak flow calibration has been achieved
for the 2 and 10 year events of the WBNM model when compared to a Rational
Method calculation. The WBNM model produces a lower peak in the 100 year event
however, this would be considered conservative when assessing non-worsening of
flows.
16
Page 22
LEGEND Data Source Notes: Project: Integrated Water Management Plan – Noosa Fair
Proposed development layout provided by TOD
Consulting for use in this investigation.
Existing Catchment Boundary
Figure 7 Existing WBNM Sub-Catchment Plan
Date: 07/02/13
Drawn by: BB
Page 23
3.3 Developed Scenario
The proposed development has been incorporated into the WBNM model by
adjusting the site sub-catchments and the fractions impervious values. Fraction
impervious values of the existing and proposed scenarios are provided in Table 16
below.
Table 16: WBNM Sub-Catchment Fraction Impervious Values – Developed Scenario
WBNM Sub- Developed Scenario Existing Scenario
Area (ha)
Catchment Impervious (%) Impervious (%)
SUBA 1.11 90 58
SUBB 0.65 90 89
SUBC 0.46 90 90
SUBD 0.31 90 90
TOTAL 2.52 - -
Peak flows tabulated in this report represent the peak values extracted from the
modelled range of storm events.
Table 17: Developed Scenario WBNM Outlet Peak Flows
Existing Peak Flow Developed Peak Flow Change in Peak Flow
(m3/s) (m3/s) (m3/s)
Outlet 1
2 year 0.73 0.69 -0.04
10 year 1.02 0.95 -0.07
100 year 1.40 1.31 -0.09
Outlet 2
2 year 0.14 0.19 0.05
10 year 0.19 0.26 0.06
100 year 0.26 0.35 0.09
Outlet 3
2 year 0.07 0.13 0.06
10 year 0.10 0.18 0.08
100 year 0.14 0.25 0.11
The catchment boundaries have changed slightly between the existing and
developed scenarios. It can be seen that the peak flows have increased to Outlets 2
and 3. This is a result of the catchment areas increasing. Peak flows from Outlet 1
have decreased as the catchment area has reduced by 0.25ha. Mitigation within the
catchment draining to Outlets 2 and 3 will be required. The developed scenario
WBNM model layout is shown in Figure 8 of this report.
18
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LEGEND Data Source Notes: Project: Integrated Water Management Plan – Noosa Fair
Proposed development layout provided by TOD
Consulting for use in this investigation.
Developed Catchment Boundary
Figure 8 Developed WBNM Sub-Catchment Plan
Detention Tank
Date: 07/05/13
Drawn by: BB
Page 25
3.4 Mitigated Scenario
When comparing the peak flows in the existing and developed scenario, increases in
the peak discharge occur at Outlets 2 and 3. As a result a detention system will be
required to be implemented in order to demonstrate non-worsening from the site.
All modeling parameters remain consistent between the developed and mitigated
scenarios, with the addition of a detention system within sub-catchments C and D.
Due to site constraints the detention system has been modeled as a
square/rectangular underground detention system. The storage details included
within the model are provided in Table 18.
Table 18: Storage and Outlet Details of Detention System
Sub-Catchment Storage Storage Height Outlet Pipe
Peak 100yr WSL (m)
Location Volume (m3) (m) Diameter (mm)
SUBC 100 1.0 375 0.87
SUBD 100 1.0 250 0.99
A comparison of the peak flows between the existing, developed and mitigated
scenarios are presented below in Table 19. It can be seen that non-worsening of
peak flows are achieved at each outlet to the site.
Table 19: Comparison of Existing, Developed and Mitigated WBNM Outlet Peak Flows
Existing Peak Developed Peak Mitigated Peak
Reduction
Flow (m3/s) Flow (m3/s) Flow (m3/s)
Outlet 1
2 0.73 0.69 0.69 -0.04
10 1.02 0.95 0.95 -0.07
100 1.40 1.31 1.31 -0.09
Outlet 2
2 0.14 0.19 0.14 0.00
10 0.19 0.26 0.19 0.00
100 0.26 0.35 0.25 -0.02
Outlet 3
2 0.07 0.13 0.07 0.00
10 0.10 0.18 0.10 -0.01
100 0.14 0.25 0.13 -0.01
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4 Conclusions
It can be seen from the results, presented in Table 10 and Table 11 that the
treatment train proposed for the development site achieves the performance
criteria set by the Sunshine Coast Regional Council. Annual Load Reductions of Total
Suspended Solids (TSS), Total Phosphorus (TP), Total Nitrogen (TN) and Gross
Pollutants (GP) between the Mitigated and Unmitigated Scenarios have been met.
It is proposed for the site to implement two detention systems within the catchment
in order to achieve Council’s non-worsening criteria. Table 19 provides a
comparison of the peak existing, developed and mitigated flows. It can be seen that
whilst peaks flows increase at Outlets 2 and 3, the modeled mitigation solutions
ensure non-worsening is achieved. Mitigation to Outlet 1 is not required due to a
reduction in overall catchment area in the developed scenario.
This plan demonstrates that effective treatment of stormwater at the proposed
development can be achieved through the integration of Water Sensitive Urban
Design (WSUD) principles. Through the incorporation of swales, GPT’s and
stormwater reuse tanks, the plan successfully demonstrates:
• Compliance with the requirements of Sunshine Coast Regional Council’s Load
Based Objectives;
• Ecological sustainability in terms of the development’s impact upon receiving
waters and the viability of the proposed site development; and
• Compliance with SCRC non-worsening of peak flows in the 2, 10 and 100 year
ARI storm event.
21
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5 References
1. WaterbyDesign (2010), “MUSIC Modelling Guidelines”.
2. WaterbyDesign (2010b), “Deemed to Comply Solutions – Stormwater Quality
Management (South East Queensland)” Version 1.0 – May 2010.
3. Sunshine Coast Council (2006), “Planning Scheme Policy No 6 – Operational
works (section 7)”.
4. Healthy Waterways (June 2006), “Water Sensitive Urban Design Technical
Design Guidelines for South East Queensland”.
5. Queensland Government – Natural Resources and Water (2007),
“Queensland Urban Drainage Manual – Volume 1 2nd Edition”.
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Appendix 1: Rational Method and WBNM Results
23
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a
aquaintel
Appendix 1: Rational Method and WBNM Results
23
ntelligent Water Management Solutions
Page 29
EXISTING WBNM RESULTS
EXISTING 2 year ARI
15 30 45 60 90 120 180
SUBA 0.41 0.43 0.35 0.41 0.34 0.32 0.24
SUBB 0.30 0.30 0.26 0.28 0.23 0.22 0.16
SUBC 0.14 0.14 0.12 0.13 0.10 0.10 0.07
SUBD 0.07 0.07 0.06 0.07 0.06 0.05 0.04
Outlet 1 0.71 0.73 0.61 0.69 0.56 0.53 0.40
Outlet 2 0.14 0.14 0.12 0.13 0.10 0.10 0.07
Outlet 3 0.07 0.07 0.06 0.07 0.06 0.05 0.04
EXISTING 10 year ARI
15 30 45 60 90 120 180
SUBA 0.58 0.61 0.50 0.58 0.49 0.47 0.37
SUBB 0.42 0.42 0.36 0.39 0.32 0.31 0.23
SUBC 0.19 0.19 0.17 0.18 0.15 0.14 0.10
SUBD 0.10 0.10 0.09 0.09 0.08 0.08 0.05
Outlet 1 1.00 1.02 0.86 0.98 0.81 0.78 0.60
Outlet 2 0.19 0.19 0.17 0.18 0.15 0.14 0.10
Outlet 3 0.10 0.10 0.09 0.09 0.08 0.08 0.05
EXISTING 100 year ARI
15 30 45 60 90 120 180
SUBA 0.82 0.83 0.72 0.82 0.66 0.63 0.51
SUBB 0.58 0.56 0.50 0.54 0.43 0.42 0.32
SUBC 0.26 0.25 0.23 0.25 0.20 0.19 0.14
SUBD 0.14 0.13 0.12 0.13 0.10 0.10 0.07
Outlet 1 1.40 1.38 1.22 1.36 1.09 1.05 0.83
Outlet 2 0.26 0.25 0.23 0.25 0.20 0.19 0.14
Outlet 3 0.14 0.13 0.12 0.13 0.10 0.10 0.07
24
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EXISTING WBNM RESULTS
EXISTING 2 year ARI
15 30
SUBA 0.41 0.43
SUBB 0.30 0.30
SUBC 0.14 0.14
SUBD 0.07 0.07
Outlet 1 0.71 0.73
Outlet 2 0.14 0.14
Outlet 3 0.07 0.07
EXISTING 10 year ARI
15 30
SUBA 0.58 0.61
SUBB 0.42 0.42
SUBC 0.19 0.19
SUBD 0.10 0.10
Outlet 1 1.00 1.02
Outlet 2 0.19 0.19
Outlet 3 0.10 0.10
EXISTING 100 year ARI
15 30
SUBA 0.82 0.83
SUBB 0.58 0.56
SUBC 0.26 0.25
SUBD 0.14 0.13
Outlet 1 1.40 1.38
Outlet 2 0.26 0.25
Outlet 3 0.14 0.13
45
0.35
0.26
0.12
0.06
0.61
0.12
0.06
45
0.50
0.36
0.17
0.09
0.86
0.17
0.09
45
0.72
0.50
0.23
0.12
1.22
0.23
0.12
60
0.41
0.28
0.13
0.07
0.69
0.13
0.07
60
0.58
0.39
0.18
0.09
0.98
0.18
0.09
60
0.82
0.54
0.25
0.13
1.36
0.25
0.13
90
0.34
0.23
0.10
0.06
0.56
0.10
0.06
90
0.49
0.32
0.15
0.08
0.81
0.15
0.08
90
0.66
0.43
0.20
0.10
1.09
0.20
0.10
120
0.32
0.22
0.10
0.05
0.53
0.10
0.05
120
0.47
0.31
0.14
0.08
0.78
0.14
0.08
120
0.63
0.42
0.19
0.10
1.05
0.19
0.10
180
0.24
0.16
0.07
0.04
0.40
0.07
0.04
180
0.37
0.23
0.10
0.05
0.60
0.10
0.05
180
0.51
0.32
0.14
0.07
0.83
0.14
0.07
~*~
aquaintel
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Page 30
DEVELOPED WBNM RESULTS
DEVELOPED 2 year ARI
15 30 45 60 90 120 180
SUBA 0.43 0.43 0.36 0.40 0.32 0.30 0.22
SUBB 0.26 0.26 0.22 0.24 0.19 0.19 0.13
SUBC 0.19 0.18 0.16 0.17 0.14 0.13 0.09
SUBD 0.13 0.13 0.11 0.12 0.10 0.09 0.06
Outlet 1 0.69 0.68 0.58 0.64 0.52 0.49 0.36
Outlet 2 0.19 0.18 0.16 0.17 0.14 0.13 0.09
Outlet 3 0.13 0.13 0.11 0.12 0.10 0.09 0.06
DEVELOPED 10 year ARI
15 30 45 60 90 120 180
SUBA 0.59 0.59 0.51 0.56 0.46 0.44 0.33
SUBB 0.36 0.35 0.31 0.34 0.28 0.27 0.20
SUBC 0.26 0.25 0.22 0.24 0.20 0.19 0.14
SUBD 0.18 0.17 0.15 0.17 0.14 0.13 0.10
Outlet 1 0.95 0.94 0.82 0.89 0.74 0.71 0.53
Outlet 2 0.26 0.25 0.22 0.24 0.20 0.19 0.14
Outlet 3 0.18 0.17 0.15 0.17 0.14 0.13 0.10
DEVELOPED 100 year ARI
15 30 45 60 90 120 180
SUBA 0.81 0.79 0.71 0.77 0.61 0.59 0.46
SUBB 0.50 0.47 0.43 0.46 0.37 0.36 0.27
SUBC 0.35 0.33 0.31 0.33 0.26 0.25 0.19
SUBD 0.25 0.23 0.21 0.23 0.18 0.18 0.13
Outlet 1 1.31 1.26 1.14 1.23 0.98 0.95 0.73
Outlet 2 0.35 0.33 0.31 0.33 0.26 0.25 0.19
Outlet 3 0.25 0.23 0.21 0.23 0.18 0.18 0.13
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DEVELOPED WBNM RESULTS
DEVELOPED 2 year ARI
15 30 45 60 90 120 180
SUBA 0.43 = =0.43 0.36 0.40 0.32 0.30 0.22
SUBB 0.26 0.26 0.22 0.24 0.19 0.19 0.13
SUBC 0.19 0.18 0.16 0.17 0.14 0.13 0.09
SUBD 0.13 0.13 0.11 0.12 0.10 0.09 0.06
Outlet 1 0.69 0.68 0.58 0.64 0.52 0.49 0.36
Outlet 2 0.19 0.18 0.16 0.17 0.14 0.13 0.09
Outlet 3 0.13 0.13 0.11 0.12 0.10 0.09 0.06
DEVELOPED 10 year ARI
15 30 45 60 90 120 180
SUBA 0.59 0.59 0.51 0.56 0.46 0.44 0.33
SUBB 0.36 0.35 0.31 0.34 0.28 0.27 0.20
SUBC 0.26 0.25 0.22 0.24 0.20 0.19 0.14
SUBD 0.18 0.17 0.15 0.17 0.14 0.13 0.10
Outlet 1 0.95 0.94 0.82 0.89 0.74 0.71 0.53
Outlet 2 0.26 0.25 0.22 0.24 0.20 0.19 0.14
Outlet 3 0.18 0.17 0.15 0.17 0.14 0.13 0.10
DEVELOPED 100 year ARI
15 30 45 60 90 120 180
SUBA 0.81 0.79 0.71 0.77 0.61 0.59 0.46
SUBB 0.50 0.47 0.43 0.46 0.37 0.36 0.27
SUBC 0.35 0.33 0.31 0.33 0.26 0.25 0.19
SUBD 0.25 0.23 0.21 0.23 0.18 0.18 0.13
Outlet 1 1.31 1.26 1.14 1.23 0.98 0.95 0.73
Outlet 2 0.35 0.33 0.31 0.33 0.26 0.25 0.19
Outlet 3 0.25 0.23 0.21 0.23 0.18 0.18 0.13
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MITIGATED WBNM RESULTS
MITIGATED 2 year ARI
15 30 45 60 90 120 180
SUBA 0.43 0.43 0.36 0.40 0.32 0.30 0.22
SUBB 0.26 0.26 0.22 0.24 0.19 0.19 0.13
SUBC 0.19 0.18 0.16 0.17 0.14 0.13 0.09
SUBD 0.13 0.13 0.11 0.12 0.10 0.09 0.06
Outlet 1 0.69 0.68 0.58 0.64 0.52 0.49 0.36
Outlet 2 0.13 0.14 0.13 0.14 0.11 0.11 0.09
Outlet 3 0.06 0.07 0.07 0.07 0.07 0.06 0.05
MITIGATED 10 year ARI
15 30 45 60 90 120 180
SUBA 0.59 0.59 0.51 0.56 0.46 0.44 0.33
SUBB 0.36 0.35 0.31 0.34 0.28 0.27 0.20
SUBC 0.26 0.25 0.22 0.24 0.20 0.19 0.14
SUBD 0.18 0.17 0.15 0.17 0.14 0.13 0.10
Outlet 1 0.95 0.94 0.82 0.89 0.74 0.71 0.53
Outlet 2 0.17 0.19 0.17 0.18 0.16 0.15 0.13
Outlet 3 0.09 0.09 0.09 0.10 0.09 0.09 0.08
MITIGATED 100 year ARI
15 30 45 60 90 120 180
SUBA 0.81 0.79 0.71 0.77 0.61 0.59 0.46
SUBB 0.50 0.47 0.43 0.46 0.37 0.36 0.27
SUBC 0.35 0.33 0.31 0.33 0.26 0.25 0.19
SUBD 0.25 0.23 0.21 0.23 0.18 0.18 0.13
Outlet 1 1.31 1.26 1.14 1.23 0.98 0.95 0.73
Outlet 2 0.24 0.25 0.24 0.25 0.21 0.20 0.18
Outlet 3 0.11 0.12 0.12 0.13 0.12 0.11 0.10
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MITIGATED WBNM RESULTS
MITIGATED 2 year ARI
15 30 45 60 90 120 180
SUBA 0.43 = =0.43 0.36 0.40 0.32 0.30 0.22
SUBB 0.26 0.26 0.22 0.24 0.19 0.19 0.13
SUBC 0.19 0.18 0.16 0.17 0.14 0.13 0.09
SUBD 0.13 0.13 0.11 0.12 0.10 0.09 0.06
Outlet 1 0.69 0.68 0.58 0.64 0.52 0.49 0.36
Outlet 2 0.13 «0.14 0.13 0.14 0.11 0.11 0.09
Outlet 3 0.06 0.07 0.07 0.07 0.07 0.06 0.05
MITIGATED 10 year ARI
15 30 45 60 90 120 180
SUBA 0.59 0.59 0.51 0.56 0.46 0.44 0.33
SUBB 0.36 0.35 0.31 0.34 0.28 0.27 0.20
SUBC 0.26 0.25 0.22 0.24 0.20 0.19 0.14
SUBD 0.18 0.17 0.15 0.17 0.14 0.13 0.10
Outlet 1 0.95 0.94 0.82 0.89 0.74 0.71 0.53
Outlet 2 0.17. 0.19 0.17 0.18 0.16 0.15 0.13
Outlet 3 0.09 0.09 0.09 0.10 0.09 0.09 0.08
MITIGATED 100 year ARI
15 30 45 60 90 120 180
SUBA 0.81 0.79 0.71 0.77 0.61 0.59 0.46
SUBB 0.50 0.47 0.43 0.46 0.37 0.36 0.27
SUBC 0.35 0.33 0.31 0.33 0.26 0.25 0.19
SUBD 0.25 0.23 0.21 0.23 0.18 0.18 0.13
Outlet 1 1.31 1.26 1.14 1.23 0.98 0.95 0.73
Outlet 2 0.24 0.25 0.24 0.25 0.21 0.20 0.18
Outlet 3 0.11 = 0.12 0.12 0.13 0.12 0.11 0.10
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RATIONAL METHOD SUMMARY & RAINFALL DATA
Project Coles Tavern Development
Project #
Rainfall IFD Input Data (Australian Rainfall and Runoff)
2 2 2 50 50 50
I1 I12 I72 I1 I12 I72 F2 F50 G
52.48 10.17 3.44 94.41 23.2 8.51 4.4 17.62 0.1
Rainfall Intensity (mm/hr)
DURATION AVERAGE RECURRENCE INTERVAL (years)
(hours) (minutes) 1 yr 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr
0.083 5 130 165 202 223 253 292 321
0.1 6 122 155 190 210 238 275 302
0.167 10 100 127 157 173 197 227 250
0.25 15 84 106 132 146 166 192 211
0.333 20 73 93 115 128 145 168 186
0.417 25 66 83 103 115 131 151 167
0.5 30 60 76 94 105 119 138 153
0.75 45 48.0 61 76 85 97 112 124
1 60 40.9 52 65 73 83 96 106
1.5 90 31.3 40.2 51 57 66 77 86
2 120 25.8 33.3 42.6 48.2 56 66 73
3 180 19.6 25.4 33.1 37.8 43.9 52 59
4.5 270 14.8 19.4 25.7 29.5 34.6 41.4 46.8
6 360 12.2 16.0 21.4 24.8 29.2 35.2 39.9
9 540 9.26 12.2 16.6 19.4 23.0 28.0 31.9
12 720 7.62 10.1 13.9 16.3 19.5 23.8 27.2
18 1080 6.03 8.01 11.1 13.1 15.7 19.2 22.0
24 1440 5.11 6.79 9.47 11.2 13.4 16.5 19.0
30 1800 4.47 5.96 8.34 9.88 11.9 14.6 16.8
36 2160 4.00 5.34 7.50 8.90 10.7 13.2 15.2
48 2880 3.34 4.47 6.31 7.52 9.06 11.2 12.9
72 4320 2.54 3.41 4.86 5.81 7.03 8.74 10.1
Catchment Data
Details: Catchment area draining to Outlet 1
Variable Value Units
Area: 2.01 ha
C10 0.87 fraction
Rational Method Summary
Adopted Time of Concentration (tc) 6.00 Minutes (or 0.10 hours)
AVERAGE RECURRENCE INTERVAL (years)
Variable 1 yr 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr
Freq Factor 0.80 0.85 0.95 1.00 1.05 1.15 1.20
Intensity (mm/hr) 121.86 154.55 189.99 210.10 238.08 274.53 302.20
Discharge (m3/s) 0.5 0.639 0.9 1.021 1.2 1.5 1.763
C:\Users\Brendon\Documents\WORK\02 Projects\10 Coles Noosa SMP\Design\Hydrology\Rational_Method 5/8/2013
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RATIONAL METHOD SUMMARY & RAINFALL DATA
Project
Project #
Rainfall IFD Input Data (Australian Rainfall and Runoff;
Coles Tavern Development
1, om 2 50, 5p 5, F2 F50 G
52.48 10.17 3.44 94.41 23.2 8.51 4.4 17.62 0.1
Rainfall Intensity (mm/hr)
DURATION AVERAGE RECURRENCE INTERVAL (years)
(hours) | (minutes) 1 yr 2yr 5 yr 10 yr 20 yr 50 yr 100 yr
0.083 5 130 165 202 223 253 292 321
0.1 6 122 155 190 210 238 275 302
0.167 10 100 127 157 173 197 227 250
0.25 15 84 106 132 146 166 192 211
0.333 20 73 93, 115 128 145 168 186
0.417 25 66 83 103 115 131 151 167
0.5 30 60 76 94 105. 119 138 153
0.75 45 48.0 61 76 85 97 112 124
1 60 40.9 52 65 73 83 96 106
1.5 90 31.3 40.2 51 57 66 77 86
2 120 25.8 33.3 42.6 48.2 56 66 73
3 180 19.6 25.4 33.1 37.8 43.9 52 59
4.5 270 14.8 19.4 25.7 29.5 34.6 41.4 46.8
6 360 12.2 16.0 21.4 24.8 29.2 35.2 39.9
9 540 9.26 12.2 16.6 19.4 23.0 28.0 31.9
12 720 7.62 10.1 13.9 16.3 19.5 23.8 27.2
18 1080 6.03 8.01 111 13.1 15.7 19.2 22.0
24 1440 5.11 6.79 9.47 11.2 13.4 16.5 19.0
30 1800 4.47 5.96 8.34 9.88 11.9 14.6 16.8
36 2160 4.00 5.34 7.50 8.90 10.7 13.2 15.2
48 2880 3.34 4.47 6.31 7.52 9.06 11.2 12.9
72 4320 2.54 3.41 4.86 5.81 7.03 8.74 10.1
Catchment Data
Details: | Catchment area draining to Outlet 1
Variable Value Units
Area: 2.01 ha
Cio 0.87 fraction
Rational Method Summary
Adopted Time of Concentration (tc) 6.00 _ Minutes (or 0.10 hours)
AVERAGE RECURRENCE INTERVAL (years)
Variable Tyr 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr
Freq Factor 0.80 0.85 0.95 1.00 1.05 1.15 1.20
Intensity (mm/hr) 121.86 154.55 189.99 210.10 238.08 274.53 302.20
Discharge (m*/s) 0.5 0.639 0.9 1.021 1.2 15 1.763
C,\Users\Brendon\Documents\WORK\02 Projects\10 Coles Noosa SMP\Design\Hydrology\Rational_Method
5/8/2013